I don't do as much deep thinking as I used to. When I was a kid, I remember imagining what it would be like if the universe was symmetrical, mirrored right down the middle. I imagined a white room, floating in space, right on the plane that separates the two halves of the universe. If you parked your spaceship outside and opened the door, you would see yourself in front of you, opening the same door. It would be the you from the other side of the universe.
Unfortunately, you couldn't talk to each other. I thought about it a lot, so trust me on this. You would have a thought, and then that thought would trigger whatever process causes you to speak, but then at the exact same time you said something, the other you would say something, and you would both say "No, please go ahead." but at the exact same time. You would probably both laugh and get a little red, but then you would feel silly for getting embarrassed in front of yourself.
And then, even though you couldn't communicate, you would have the most amazing experience together. You would walk towards the center of the room, your space shoes tapping out the same tempo on the white floor, stopping just a couple feet apart. Maybe you would take your space gloves and space helmet off so you could give each other Eskimo kisses and exchange the perfect high-five.
Then you would think for a minute, "Should I?" and you would both nod and sort of start to circle around each other. And then you would walk away from each other and leave through the other door, into the other half of the universe. You would get into her spaceship, with her mix CD in the CD player, and it would be the same as the mix CD in the spaceship that you had left behind (it would even start playing right where yours had stopped) and you would fly home.
Sometimes, at night, you might feel a little creepy about it. You would think about how you were sleeping in somebody else's bed, in somebody else's whole world. But that would only last for a second, and then you would think about how she was sleeping in your bed, and how nice the time you spent together was, and you would soon snuggle under the covers and fall asleep.